Geological Survey (U.S.). (1911). Conventional signs adopted by U.S. Geographic Board. [publisher not identified].
Chicago Style (17th ed.) CitationGeological Survey (U.S.). Conventional Signs Adopted by U.S. Geographic Board. Washington: [publisher not identified], 1911.
MLA (9th ed.) CitationGeological Survey (U.S.). Conventional Signs Adopted by U.S. Geographic Board. [publisher not identified], 1911.
Warning: These citations may not always be 100% accurate.